Trialkylamine salt-functionalized polyphenylene ethers, methods for their preparation, and compositions containing them

ABSTRACT

Functionalized polyphenylene ethers are prepared by mixing with various trialkylammonium maleates or fumarates in the melt, in the absence of free radical initiators. They are useful in the preparation of resinous compositions comprising polyphenylene ethers and polyamides or polyesters. Such resinous compositions preferably also contain impact modifiers.

This invention relates to the functionalization of polyphenylene ethers,and to uses for the polyphenylene ethers so functionalized.

Various compositions comprising polyphenylene ethers (also known aspolyphenylene oxides) and polyamides or linear polyesters, illustratedby Nylon-6, Nylon-66, poly(ethylene terephthalate) and poly(butyleneterephthalate), are of interest because of their high solvent resistanceand potentially high impact strength. However, such compositionstypically undergo phase separation and delamination because of thepresence therein of large, incompletely dispersed polyphenylene etherparticles and the lack of phase interaction between the two resinphases.

According to U.S. Pat. No. 4,315,086 and European patent application No.24,120, compositions comprising polyphenylene ethers and polyamides,having high impact strength and solvent resistance, may be prepared bymelt blending the two polymers with various olefinic or acetyleniccarboxyllic acids, functional derivatives thereof or otherfunctionalized compounds, and optionally with impact modifiers such ashigh impact polystyrenes and partially hydrogenated styrene-butadieneblock copolymers. Japenese Kokai No. 84/66452 describes similarcompositions prepared by using a polyphenylene ether which has beenpretreated with a similar olefinic compound in the mandatory presence ofa free radical initiator. There is, however, continuing interest inpreparing compositions of this type having still higher impact strengthsand other improvements in properties.

A principal object of the present invention, therefore, is to providenovel polyphenylene ether compositions.

A further object is to provide functionalized polyphenylene ethers whichform compatible compositions when blended with such polymers aspolyamides and linear polyesters.

A still further object is to provide polyphenylene ether-polyamidecompositions having high impact strength and solvent resistance.

Other objects will in part be obvious and will in part appearhereinafter.

It has been discovered that polyphenylene ethers may be functionalizedwith trialkylamine salts of certain olefinic polycarboxylic acids, andthat the functionalized polyphenylene ethers thus prepared formcompatible blends having high impact strength with such resins aspolyamides and polyesters. Such compatibilization may be achieved priorto or simultaneously with blending with said resins.

In one of its aspects, therefore, the present invention includesfunctionalized polyphenylene ethers and a method for their preparation,said method comprising mixing said polyphenylene ether in the melt withat least one functionalizing compound commprising a trialkylamine saltof maleic or fumaric acid.

The polyphenylene ethers used in the present invention are a well knownclass of polymers. They are widely used in industry, especially asengineering plastics in applications requiring toughness and heatresistance. Since their discovery, they have given rise to numerousvariations and modifications of all which are applicable to the presentinvention, including but not limited to those described hereinafter.

The polyphenylene ethers comprise a plurality of structural units havingthe formula ##STR1## In each of said units independently, each Q¹ isindependently halogen, primary or secondary lower alkyl (i.e., alkylcontaining up to 7 carbon atoms), phenyl, haloalkyl, aminoalkyl,hydrocarbonoxy, or halohydrocarbonoxy wherein at least two carbon atomsseparate the halogen and oxygen atoms; and each Q² is independentlyhydrogen, halogen, primary or secondary lower alkyl, phenyl, haloalkyl,hydrocarbonoxy or halohydrocarbonoxy as defined for Q¹. Examples ofsuitable primary lower alkyl groups are methyl, ethyl, n-propyl,n-butyl, isobutyl, n-amyl, isoamyl, 2-methylbutyl, n-hexyl,2,3-dimethylbutyl, 2-, 3- or 4-methylpentyl and the corresponding heptylgroups. Examples of secondary lower alkyl groups are isopropyl,sec-butyl and 3-pentyl. Preferably, any alkyl radicals are straightchain rather than branched. Most often, each Q¹ is alkyl or phenyl,especially C₁₋₄ alkyl, and each Q² is hydrogen. Suitable polyphenyleneethers are disclosed in a large number of patents.

Both homopolymer and copolymer polyphenylene ethers are included.Suitable homopolymers are those containing, for example,2,6-dimethyl-1,4-phenylene ether units. Suitable copolymers includerandom copolymers containing such units in combination with (forexample) 2,3,6-trimethyl-1,4-phenylene ether units. Many suitable randomcopolymers, as well as homopolymers, are disclosed in the patentliterature.

Also included are polyphenylene ethers containing moieties which modifyproperties such as molecular weight, melt viscosity and/or impactstrength. Such polymers are described in the patent literature and maybe prepared by grafting onto the polyphenylene ether in known mannersuch vinyl monomers as acrylonitrile and vinylaromatic compounds (e.g.,styrene), or such polymers as polystyrenes and elastomers. The producttypically contains both grafted and ungrafted moieties. Other suitablepolymers are the coupled polyphenylene ethers in which the couplingagent is reacted in known manner with the hydroxy groups of twopolyphenylene ether chains to produce a higher molecular weight polymercontaining the reaction product of the hydroxy groups and the couplingagent. Illustrative coupling agents are low molecular weightpolycarbonates, quinones, heterocycles and formals.

The polyphenylene ether generally has a number average molecular weightwithin the range of about 3,000-40,000 and a weight average molecularweight within the range of about 20,000-80,000, as determined by gelpermeation chromatography. Its intrinsic viscosity is most often in therange of about 0.35-0.6 dl./g., as measured in chloroform at 25° C.

The polyphenylene ethers are typically prepared by the oxidativecoupling of at least one corresponding monohydroxyaromatic compound.Particularly useful and readily available monohydroxyaromatic compoundsare 2,6-xylenol (wherein each Q¹ is methyl and each Q² is hydrogen),whereupon the polymer may be characterized as apoly(2,6-dimethyl-1,4-phenylene ether), and 2,3,6-trimethylphenol(wherein each Q¹ and one Q² is methyl and the other Q² is hydrogen).

A variety of catalyst systems are known for the preparation ofpolyphenylene ethers by oxidative coupling. There is no particularlimitation as to catalyst choice and any of the known catalysts can beused. For the most part, they contain at least one heavy metal compoundsuch as a copper, manganese or cobalt compound, usually in combinationwith various other materials.

A first class of preferred catalyst systems consists of those containinga copper compound. Such catalysts are disclosed, for example, in U.S.Pat. Nos. 3,306,874, 3,306,875, 3,914,266 and 4,028,341. They areusually combinations of cuprous or cupric ions, halide (i.e., chloride,bromide or iodide) ions and at least one amine.

Catalyst systems containing manganese compounds constitute a secondpreferred class. They are generally alkaline systems in which divalentmanganese is combined with such anions as halide, alkoxide or phenoxide.Most often, the manganese is present as a complex with one or morecomplexing and/or chelating agents such as dialkylamines, alkanolamines,alkylenediamines, o-hydroxyaromatic aldehydes, o-hydroxyazo compounds,ω-hydroxyoximes (monomeric and polymeric), o-hydroxyaryl oximes andβ-diketones. Also useful are known cobalt-containing catalyst systems.Suitable manganese and cobalt-containing catalyst systems forpolyphenylene ether preparation are known in the art by reason ofdisclosure in numerous patents and publications.

Particulary useful polyphenylene ethers for the purposes of thisinvention are those which comprise molecules having at least one of theend groups of the formulas ##STR2## wherein Q¹ and Q² are as previouslydefined; each R¹ is independently hydrogen or alkyl, with the provisothat the total number of carbon atoms in both R¹ radicals is 6 or less;and each R² is independently hydrogen or a C₁₋₆ primary alkyl radical.Preferably, each R¹ is hydrogen and each R² is alkyl, especially methylor n-butyl.

Polymers containing the aminoalkyl-substituted end groups of formula IImay be obtained by incorporating an appropriate primary or secondarymonoamine as one of the constituents of the oxidative coupling reactionmixture, especially when a copper- or manganese-containing catalyst isused. Such amines, especially the dialkylamines and preferablydi-n-butylamine and dimethylamine, frequently become chemically bound tothe polyphenylene ether, most often by replacing one of the α-hydrogenatoms on one or more Q¹ radicals. The principal site of reaction is theQ¹ radical adjacent to the hydroxy group on the terminal unit of thepolymer chain. During further processing and/or blending, theaminoalkyl-substituted end groups may undergo various reactions,probably involving a quinone methide-type intermediate of the formula##STR3## with numerous beneficial effects often including an increase inimpact strength and compatibilization with other blend components.Reference is made to U.S. Pat. Nos. 4,054,553, 4,092,294, 4,477,649,4,477,651 and 4,517,341, the disclosures of which are incorporated byreference herein.

Polymers are 4-hydroxybiphenyl end groups of formula III are typicallyobtained from reaction mixtures in which a by-product diphenoquinone ofthe formula ##STR4## is present, especially in a copper-halide-secondaryor tertiary amine system. In this regard, the disclosure of U.S. Pat.No. 4,477,649 is again pertinent as are those of U.S. Pat. Nos.4,234,706 and 4,482,697, which are also incorporated by referenceherein. In mixtures of this type, the diphenoquinone is ultimatelyincorporated into the polymer in substantial proportions, largely as anend group.

In many polyphenylene ethers obtained under the above-describedconditions, a substantial proportion of the polymer molecules, typicallyconstituting as much as about 90% by weight of the polymer, contain endgroups having one or frequently both of formulas II and III. It shouldbe understood, however, that other end groups may be present and thatthe invention in its broadest sense may not be dependent on themolecular structures of the polyphenylene ether end groups.

It will be apparent to those skilled in the art from the foregoing thatthe polyphenylene ethers contemplated for use in the present inventioninclude all those presently known, irrespective of variations instructural units or anchillary chemical features.

As previously described, the functionalizing compound employed accordingto the present invention is at least one trialkylammonium maleate orfumarate. The identity of the trialkylamine is not critical but itgenerally contains primary alkyl groups having from 1 to about 12 carbonatoms. Aryl-substituted alkyl groups such as benzyl and phenethyl areincluded.

The preferred trialkylamines, by reason of their availability andparticular suitability, are triethylamine, tri-n-butylamine andtribenzylamine. Fumarates are particularly preferred.

Functionalized polyphenylene ethers may be conveniently preparedaccording to the invention by merely blending the two reagents underconditions adapted for the formation of the intimate blend, and attemperature high enough to prepare a melt. Typical temperatures arewithin the range of about 230°-390° C.

It is preferred that mixing be in the absence of free radicalinitiators. The fact that some type of interaction takes place underthese conditions, and that the product is useful for compatibilizingblends as described hereinafter, is quite unexpected in view of theaforementioned Japanese Kokai No. 84/66452, which explicitly states byway of comparative test results that similar products prepared from thefree acids are of little or no utility for this purpose.

The proportions of polyphenylene ether and functionalizing compound arenot critical, provided the functionalizing compound is used in minorproportions compared to the polyphenylene ether. Most often, about0.1-10 parts and preferably about 1.0-5 parts of functionalizing agentare present per 100 parts of polyphenylene ether.

Suitable mixing conditions often include extrusion, which may beconveniently effected in a screw-type or similar extruder which suppliesa substantial shearing force to the composition. In certain instances,it may be advantageous to vacuum vent the extruder by connecting thevent thereof to a vacuum pump capable of drawing a vacuum of about 20torr or less. It is also sometimes found advantageous to extrude themixture more than once, thereby ensuring effective blending.

The precise chemical nature of the functionalization which takes placeupon practice of the method of this invention is not known withcertainty. The principal reaction (if any) may be a thermally initiatedfree radical interaction of the carbon-carbon double bond with thearomatic rings of the substituents thereon, especially the latter, toproduce a product which may include single moieties and/or grafted sidechains derived from the functionalizing agent. However, the invention isin no way dependent on theory.

As more fully described hereinafter, a principal utility of thefunctionalized polyphenylene ethers of this invention is in thepreparation of polyphenylene ether-polyamide compositions. Suchcompositions typically also contain impact modifying resins, and it isfrequently preferred to melt-blend at least one such impact modifierwith the polyphenylene ether and the functionalizing compound.

Impact modifiers for polyphenylene ether-polyamide compositions are wellknown in the art. They are typically derived from one or more monomersselected from the group consisting of olefins, vinyl aromatic monomers,acrylic and alkylacrylic acids and their ester derivatives as well asconjugated dienes. Especially preferred impact modifiers are the rubberyhigh-molecular weight materials including natural and syntheticpolymeric materials showing elasticity at room temperature. They includeboth homopolymers and copolymers, including random, block, radial block,graft and core-shell copolymers as well as combinations thereof.

Polyolefins or olefin-based copolymers employable in the inventioninclude low density polyethylene, high density polyethylene, linear lowdensity polyethylene, isotactic polypropylene, poly(1-butene),poly(4-methyll-pentene), propylene-ethylene copolymers and the like.Additional olefin copolymers include copolymers of one or moreα-olefins, particularly ethylene, with copolymerizable monomersincluding, for example, vinyl acetate, acrylic acids and alkylacrylicacids as well as the ester derivatives thereof including, for example,ethylene-acrylic acid, ethyl acrylate, methacrylic acid, methylmethacrylate and the like. Also suitable are the ionomer resins, whichmay be wholly or partially neutralized with metal ions.

A particularly useful class of impact modifiers are those derived fromthe vinyl aromatic monomers. These include, for example, modified andunmodified polystyrenes, ABS type graft copolymers, AB and ABA typeblock and radial block copolymers and vinyl aromatic conjugated dienecoreshell graft copolymers. Modified and unmodified poolystyrenesinclude homopolystyrenes and rubber modified polystyrenes, such asbutadiene rubber-modified polystyrene (otherwise referred to as highimpact polystyrene or HIPS). Additional useful polystyrenes includecopolymers of styrene and various monomers, including, for example,poly(styreneacrylonitrile) (SAN), styrene-butadiene copolymers as wellas the modified alpha- and para-substituted styrenes and any of thestyrene resins disclosed in U.S. Pat. No. 3,383,435, herein incorporatedby reference. ABS types of graft copolymers are typified as comprising arubber polymeric backbone derived from a conjugated diene alone or incombination with a monomer copolymerizable therewith having graftedthereon at least one monomer, and preferably two, selected from thegroup consisting of monoalkenylarene monomers and substitutedderivatives thereof as well as acrylic monomers such as acrylonitrilesand acrylic and alkylacrylic acids and their esters.

An especially preferred subclass of vinyl aromatic monomer-derivedresins is the block copolymers comprising monoalkenyl arene (usuallystyrene) blocks and conjugated diene (e.g., butadiene or isoprene)blocks and represented as AB and ABA block copolymers. The conjugateddiene blocks may be partially or entirely hydrogenated.

Suitable AB type block copolymers are disclosed in, for example, U.S.Pat, Nos. 3,078,254; 4,402,159; 3,297,793; 3,265,765 and 3,594,452 andUK Pat. No. 1,264,741, all incorporated herein by reference. Exemplaryof typical species of AB block copolymers there may be given:

polystyrene-polybutadiene (SBR)

polystyrene-polyisoprene and

poly(alpha-methylstyrene)-polybutadiene.

Such AB block copolymers are available commercially from a number ofsources, including Phillips Petroleum under the trademark SOLPRENE.

Additionally, ABA triblock copolymers and processes for their productionas well as hydrogenation, if desired, are disclosed in U.S. Pat. Nos.3,149,182; 3,231,635; 3,462,162; 3,287,333; 3,595,942; 3,694,523 and3,842,029, all incorporated herein by reference.

Examples of triblock copolymers include:

polystyrene-polybutadiene-polystyrene (SBS),

polystyrene-polyisoprene-polystyrene (SIS),

poly(α-methylstyrene)-polybutadiene-poly(α-methylstyrene) and

poly(α-methylstyrene)-polyisoprene-poly(α-methylstyrene).

Particularly preferred triblock copolymers are available commercially asCARIFLEX®, KRATON D® and KRATON G® from Shell.

Another class of impact modifiers is derived from conjugated dienes.While many copolymers containing conjugated dienes have been discussedabove, additional conjugated diene modifier resins include, for example,homopolymers and copolymers of one or more conjugated dienes including,for example, polybutadiene, butadiene-styrene copolymers,isoprene-isobutylene copolymers, chlorobutadiene polymers,butadiene-acrylonitrile copolymers, polyisoprene and the like.Ethylene-propylene-diene monomer rubbers may also be used. These EPDM'sare typified as comprising predominantly ethylene units, a moderateamount of propylene units and up to about 20 mole percent ofnon-conjugated diene monomer units. Many such EPDM's and processes forthe production thereof are disclosed in U.S. Pat. Nos. 2,933,480;3,000,866; 3,407,158; 3,093,621 and 3,379,701, incorporated herein byreference.

Other suitable impact modifiers are the core-shell type graftcopolymers. In general, these have a predominantly conjugated dienerubbery core or a predominantly cross-linked acrylate rubbery core andone or more shells polymerized thereon and derived from monoalkenylareneand/or acrylic monomers alone or, preferably, in combination with othervinyl monomers. Such core-shell copolymers are widely availablecommericially, for example, from Rohm and Haas Company under the tradenames KM-611, KM-653 and KM-330, and are described in U.S. Pat. Nos.3,808,180; 4,034,013; 4,096,202; 4,180,494 and 4,292,233.

Also useful are the core-shell copolymers wherein an interpenetratingnetwork of the resins employed characterizes the interface between thecore and shell. Especially preferred in this regard are the ASA typecopolymers available from General Electric Company and sold as GELOY®resin and described in U.S. Pat. No. 3,944,631.

In addition, there may be employed the abovedescribed polymers andcopolymers having copolymerized therewith or grafted thereon monomershaving functional groups and/or polar or active groups. Finally, othersuitable impact modifiers include Thiokol rubber, polysulfide rubber,polyurethane rubber, polyether rubber (e.g., polypropylene oxide),epichlorohydrin rubber, ethylenepropylene rubber, thermoplasticpolyester elastomers and thermoplastic ether-ester elastomers.

The proportion of impact modifier is subject to wide variation.Generally, about 1-150 parts by weight thereof are employed per 100parts of polyphenylene ether. When the impact modifier is a diblock ortriblock copolymer, it is usually present in an amount up to about 50parts per 100 parts of polyphenylene ether.

The preparation of the functionalized polyphenylene ethers of thisinvention is illustrated by the following examples. All parts are byweight. The polyphenylene ether used in these examples was apoly-(2,6-dimethyl-1,4-phenylene ether) having a number averagemolecular weight of about 20,000 and an intrinsic viscosity inchloroform at 25° C. of 0.48-0.49 dl./g.

EXAMPLES 1-5

Mixtures of 49 parts of polyphenylene ether, 10 parts of a partiallyhydrogenated styrene-butadiene-styrene copolymer having astyrene-butadiene ratio of 27:73 and a number average molecular weightof about 74,000, and various proportions of bis-trialkylammoniumfumarates were tumble mixed on a roll mill for 30 minutes and extrudedin a Welding Engineers twin screw extruder at 400 rpm. and 288° C., withfull vacuum vent, to yield the desired functionalized polyphenyleneethers. The fumarates and proportions thereof were as follows:

Example 1 - triethylammonium fumarate, 0.7 part.

Example 2 - triethylammonium fumarate, 1.5 parts.

Example 3 - tri-n-butylammonium fumarate, 0.7 part.

Example 4 - tri-n-butylammonium fumarate, 1..5 parts.

Example 5 - tribenzylammonium fumarate, 0.7 part.

As previously noted, the functionalized polyphenylene ethers of thisinvention are useful in the preparation of blends of polyphenyleneethers with polyamides and linear polyesters. For this purpose,functionalization may be effected before or during blending with thepolyamide. Prior functionalization is generally preferred; that is, itis preferred that a functionalized polyphenylene ether as describedhereinabove be subsequently blended with the polyamide.

Other aspects of the invention, therefore, are a method for preparing aresin composition which comprises mixing in the melt at least onepolyphenylene ether, at least one polyamide and at least oneabove-described functionalizing compound, and compositions so prepared.A preferred embodiment comprises:

(A) mixing at least a portion of said polyphenylene ether in the melt,in the absence of free radical initiators, with said functionalizingcompound, thereby producing a functionalized polyphenylene ether; andsubsequently

(B) melt-blending said functionalized polyphenylene ether with at leastone polyamide; with the proviso that there is also blended into saidcomposition at least one impact modifying resin for polyphenyleneether-polyamide compositions.

Suitable polyamides may be made by any known method, including thepolymerization of a monoamino-monocarboxylic acid or a lactum thereofhaving at least 2 carbon atoms between the amino and carboxylic acidgroup, of substantially equimolar proportions of a diamine whichcontains at least 2 carbon atoms between the amino groups and adicarboxylic acid, or of a monoaminocarboxylic acid or a lactum thereofas defined above together with substantially equimolar proportions of adiamine and a dicarboxylic acid. (The term "substantially equimolar"proportions includes both strictly equimolar proportions and slightdepartures therefrom which are involved in conventional techniques forstabilizing the viscosity of the resultant polyamides.) The dicarboxylicacid may be used in the form of a functional derivative thereof, forexample, an ester or acid chloride.

Examples of the aforementioned monoamino-monocarboxylic acids or lactamsthereof which are useful in preparing the polyamides include thosecompounds containing from 2 to 16 carbon atoms between the amino andcarboxylic acid groups, said carbon atoms forming a ring with the--CO--NH--group in the case of a lactum. As particular examples ofaminocarboxylic acids and lactums there may be mentioned ε-aminocaproicacid, butyrolactam, pivalolactam, ε-caprolactam, capryllactam,enantholactam, undecanolactam, dodecanolactam and 3- and 4-aminobenzoicacids.

Diamines suitable for use in the preparation of the polyamides includethe straight chain and branched chain alkyl, aryl and alkaryl diamines.Such diamines include, for example, those represented by the generalformula

    H.sub.2 N(CH.sub.2).sub.n NH.sub.2

wherein n is an integer of from 2 to 16. Illustrative diamines aretrimethylenediamine, tetramethylenediamine, pentamethylenediamine,octamethylenediamine, hexamethylenediamine (which is often preferred),trimethylhexamethylenediamine, m-phenylenediamine and m-xylylenediamine.

The dicarboxylic acids may be represented by the formula

    HOOC--Y--COOH

wherein Y is a divalent aliphatic or aromatic group containing at least2 carbon atoms. Examples of aliphatic acids are sebacic acid,octadecanedioic acid, suberic acid, glutaric acid, pimelic acid andadipic acid. Aromatic acids, such as isophthalic and terephthalic acids,are preferred.

Typical examples of the polyamides or nylons, as these are often caled,include, for example, polyamide-6, 66, 11, 12, 63, 64, 6/10 and 6/12 aswell as polyamides from terephthalic acid and/or isophthalic acid andtrimethylhexamethylenediamine; from adipic acid and m-xylylenediamines;from adipic acid; azelaic acid and 2,2-bis-(p-aminocyclohexyl) propaneand from terephthalic acid and 4,4'-diaminodicyclohexylmethane. Mixturesand/or copolymers of two or more of the foregoing polyamides orprepolymers thereof, respectively, are also within the scope of thepresent invention. Preferred polyamides are polyamide-6, 66, 11 and 12,most preferably polyamide-66.

Linear polyesters which may be blended with the functionalizedpolyphenylene ethers include thermoplastic poly(alkylene dicarboxylates)and alicyclic analogs thereof. They typically comprise structural unitsof the formula ##STR5## wherein R³ is a saturated divalent aliphatic oralicyclic hydrocarbon radical containing about 2-10 and usually about2-6 carbon atoms and A is a divalent aromatic radical containing about6-20 carbon atoms. They are ordinarily prepared by the reaction of atleast one diol such as ethylene glycol, 1,4-butanediol or1,4-cyclohexanedimethanol with at least one aromatic dicarboxylic acidsuch as isophthalic or terephthalic acid, or lower alkyl ester thereof.The polyalkylene terphthalates, particularly polyethylene andpolybutylene terephthalate and especially the latter, are preferred.Such polyesters are known in the art as illustrated by the followingpatents: U.S. Pat. Nos. 2,465,319, 3,047,539, 2,720,502, 3671,487,2,727,881, 3,953,394, 2,822,348, 4,128,526.

The polyphenylene ether which is blended with the polyamide or polyestermay be solely functionalized polyphenylene ether prepared by the methodof this invention. However, it is also contemplated to include bothfunctionalized and unfunctionalized polyphenylene ether in the blend,the latter being present in an amount up to about 90% by weight of totalpolyphenylene ether. The polyphenylene ether-polyamide or polyesterblend generally contains about 5-75% by weight polyphenylene ether andabout 25-95% polyamide or polyester.

There is preferably also blended into the polyphenylene ether-polyamidecomposition at least one of the previously identified impact modifiers.The impact modifier may be introduced at any time during the blendingoperation, or over an extended time period separate from or concurrentwith the addition of other blend constituents.

It is preferred, however, to complete addition of the impact modifierbefore beginning polyamide addition. More preferably, all of the impactmodifier is blended with the polyphenylene ether concurrent withfunctionalization thereof as described hereinabove.

Blending may be achieved by known methods, typically involving meltblending and extrusion. In one suitable method, the functionalizedpolyphenylene ether is prepared in a first extruder, preferably in thepresence of the impact modifier as previously noted, and subsequentlyblended in a second extruder with the remaining constituents, includingpolyamide and any unfunctionalized polyphenylene ether.

It is also possible to perform the entire blending operaiton in alateral-feed extruder, in which it is possible to supply constituents atvarious points. Under these conditions, the polyphenylene ether, thefunctionalizing agent and preferably the impact modifier are supplied atthe rear of the extruder, and any remaining constituents are supplied atone or more points nearer its outlet.

The preparation of the polyphenylene ether-polyamide compositions ofthis invention is illustrated by the following examples.

EXAMPLES 6-10

The compositions of Examples 1-5 (each prepared from 49 parts ofpolyphenylene ether, 10 parts of impact modifier and varying amount oftrialkylammonium fumarate) were combined with 41 parts of a commerciallyavailable polyamide-66 and extruded under the conditions described inExamples 1-5. The extrudates were quenched in water, pelletized, driedfor 3-4 hours at 95°-105° C. and injection molded into test specimensfor the notched Izod impact test. The results of the test are given inthe following table.

    ______________________________________                                                   Functionalized                                                                              Impact strength,                                     Example    polyphenylene ether                                                                         joules/m.                                            ______________________________________                                        6          1             123                                                  7          2             748                                                  8          3             171                                                  9          4             748                                                  10         5             748                                                  ______________________________________                                    

What is claimed is:
 1. A method for functionalizing a polyphenylene ether which comprises mixing said polyphenylene ether in the melt with at least one functionalizing compound comprising a trialkylamine salt of maleic or fumaric acid.
 2. A method according to claim 1 which is effected in the absence of free radical initiators, and wherein the polyphenylene ether comprises a plurality of structural units having the formula ##STR6## and in each of said units independently, each Q¹ is independently halogen, primary or secondary lower alkyl, phenyl, haloalkyl, aminoalkyl, hydrocarbonoxy, or halohydrocarbonoxy wherein at least two carbon atoms separate the halogen and oxygen atoms; and each Q² is independently hydrogen, halogen, primary or secondary lower alkyl, phenyl, haloalkyl, hydrocarbonoxy or halohydrocarbonoxy as defined for Q¹.
 3. A functionalized polyphenylene ether prepared by the method of claim
 2. 